Hidetoshi Tsukamoto's scientific contributions

Publications (62)

Publications citing this author (961)

    • [37,38] Noma et al., described a signifi cant relationship between the severity of periodontal disease and DR, with high IL-6 concentrations in the retinal vitreous fl uid of the studied patients. [15] Although the reasons for this increase had not been appointed, the presence of immune alterations in these patients, with the subsequent increase in infl ammatory mediator production, could be responsible for the damage observed both at periodontal level and elsewhere. Whether periodontal disease is a risk factor for DR or a coincidental fi nding remains to be determined.
    [Show abstract] [Hide abstract] ABSTRACT: Periodontal disease in diabetic patients can compromise a patient's ability to maintain a proper metabolic control and may be associated with diabetic complication. This study was designed to evaluate the frequency of periodontal disease in patients with type 2 diabetes mellitus (DM) and how this was related with the presence of diabetic retinopathy (DR). A comparison was made of periodontal parameters (plaque index (PI), community periodontal index of treatment needs (CPITN), periodontal disease severity measured in quartiles of probing depth (PD), and clinical attachment loss (CAL)) in a group of diabetic patients with retinopathy (n = 84) versus a group of diabetic patients without retinopathy (n = 129). In addition, 73 age- and sex-matched individuals were selected to serve as the control group. Analysis was performed to evaluate the relationships between periodontal disease and DR. In terms of PI, no statistically significant differences were observed, so, oral hygiene was similar in both groups. Diabetic patients with retinopathy had greater CPITN (P < 0.001) and more severe periodontal disease (P < 0.001) than no retinopathy. Also, our results indicated a relationship between type 2 DM and periodontal disease. The patients with diabetes retinopathy appear to show increased periodontal disease susceptibility.
    Full-text · Article · Mar 2014
    • The profile of corneal deformation over time is bell-shaped (Figure 1), while that for elderly individuals differs because, after corneal deformation, the corneal shaped remains fixed for a few milliseconds, then starts to return until the cornea reaches its original shape and position [3,28]. A line graph of the changes in the extent of central corneal deformation is bell-shaped with a shoulder bump at the late phase in older subjects [3,28]. The effects of contact lens use on corneal bioproperties are different from those caused by aging.
    [Show abstract] [Hide abstract] ABSTRACT: To evaluate the displacement of the central ocular surface during non-contact tonometry with and without soft contact lenses and determine the factors associated with the displacement of the central ocular surface and intraocular pressure (IOP) reading changes caused by wearing soft contact lenses (CLs). One eye each in 21 subjects was studied. The cornea was photographed using a high-speed camera at 5,000 frames/sec during non-contact tonometry without contact lenses (NCL), with -5.0 diopters (D), -0.5 D and +5.0 D CL. The displacement of the ocular surface and the factors affecting displacement at the IOP reading and maximum displacement time were investigated. The IOP readings while wearing +5 D CL were significantly higher than those obtained while wearing -5 D CL. The ocular surface displacement between +5 D CL and other groups were significantly different. A significant positive correlation was found between the ocular surface displacement of subjects at the IOP reading time and the IOP obtained with the non-contact tonometer. A significant negative correlation was found between the ocular surface curvature and the IOP obtained using the non-contact tonometer. The radius of curvature of the ocular surface affected the displacement during the IOP reading and maximum displacement time. Our results indicate that soft contact lens use changes the ocular surface behavior and IOP readings during non-contact tonometry. The radius of curvature of the eye affects the ocular surface displacement and IOP readings in this situation.
    Full-text · Article · Apr 2014
    • mM) D-glucose for 48 h. Cells incubated in 27.5 mM mannitol (M) served as osmotic control [32].
    [Show abstract] [Hide abstract] ABSTRACT: Diabetic retinopathy is a preventable microvascular diabetic complication and a leading cause of vision loss. Retinal pigment epithelial cell apoptosis is an early event in diabetic retinopathy. Taurine is reportedly beneficial for diabetic retinopathy and is abundant in the fruit of Lycium barbarum (LB). We have investigated the effect of pure taurine and an extract of LB rich in taurine on a model of diabetic retinopathy, the retinal ARPE-19 cell line exposed to high glucose. We demonstrate for the first time that LB extract and the active ligand, taurine, dose dependently enhance cell viability following high glucose treatment in the ARPE-19 retinal epithelial cell line. This cytoprotective effect was associated with the attenuation of high glucose-induced apoptosis, which was shown by characteristic morphological staining and the dose-dependent decrease in the number of apoptotic cells, determined by flow cytometry. Moreover, we have shown that LB extract and taurine dose dependently downregulate caspase-3 protein expression and the enzymatic activity of caspase-3. We conclude that taurine, a major component of LB, and the LB extract, have a cytoprotective effect against glucose exposure in a human retinal epithelial cell line and may provide useful approaches to delaying diabetic retinopathy progression.
    Full-text · Article · Apr 2012
    • A study using the Sumi questionnaire [10, 42] also noted that the inferior field is the most important area for near work such as reading and writing. Further experiments would be required to assess the associations between reading performance and more detailed VF quantification, for example, consideration of each point of the total deviation or using a clustered VF [43, 44] to evaluate which part of the VF is important in silent reading. It is necessary to evaluate combinations of subjective reading disability and objective eye movements during reading.
    [Show abstract] [Hide abstract] ABSTRACT: Objective To investigate the relationship between silent reading performance and visual field defects in patients with glaucoma using an eye tracking system. Methods Fifty glaucoma patients (Group G; mean age, 52.2 years, standard deviation: 11.4 years) and 20 normal controls (Group N; mean age, 46.9 years; standard deviation: 17.2 years) were included in the study. All participants in Group G had early to advanced glaucomatous visual field defects but better than 20/20 visual acuity in both eyes. Participants silently read Japanese articles written horizontally while the eye tracking system monitored and calculated reading duration per 100 characters, number of fixations per 100 characters, and mean fixation duration, which were compared with mean deviation and visual field index values from Humphrey visual field testing (24–2 and 10–2 Swedish interactive threshold algorithm standard) of the right versus left eye and the better versus worse eye. Results There was a statistically significant difference between Groups G and N in mean fixation duration (G, 233.4 msec; N, 215.7 msec; P = 0.010). Within Group G, significant correlations were observed between reading duration and 24–2 right mean deviation (rs = -0.280, P = 0.049), 24–2 right visual field index (rs = -0.306, P = 0.030), 24–2 worse visual field index (rs = -0.304, P = 0.032), and 10–2 worse mean deviation (rs = -0.326, P = 0.025). Significant correlations were observed between mean fixation duration and 10–2 left mean deviation (rs = -0.294, P = 0.045) and 10–2 worse mean deviation (rs = -0.306, P = 0.037), respectively. Conclusions The severity of visual field defects may influence some aspects of reading performance. At least concerning silent reading, the visual field of the worse eye is an essential element of smoothness of reading.
    Full-text · Article · Jan 2017
    • These factors seem to influence corneal deformation and stiffness. However, the measured value of eye stiffness by the contact method (60 ∼ 140[N/m] for healthy subjects) is close to the analytical result in comparison with the stiffness measured by the non-contact method (500 ∼ 3500[N/m] for healthy subjects [3]). This indicates the contact method is appropriate for the evaluation of the contact stiffness.
    [Show abstract] [Hide abstract] ABSTRACT: Goldmann applanation tonometry is commonly used for measuring intraocular pressure (IOP) to diagnose glaucoma. However, the measured IOP by conventional applanation tonometry is valid only under the assumption that all subjects have the same structural eye stiffness. This paper challenges in vivo measurement of eye stiffness with a noninvasive approach and investigates individual differences of eye stiffness. Eye stiffness is defined by the applied force and displacement of the cornea. The displacement is detected based on captured images by a high resolution camera. The experimental results show that the measured stiffness nicely matches the analytical result that is derived from a simple spherical deformation model with an internal pressure. However, some subjects have different eye stiffness even with the same IOP. IOP with abnormal stiffness may be over/underestimated by conventional applanation tonometry. The proposed eye stiffness measurement can help detect the misestimated eye and it contributes to the early detection of glaucoma.
    Full-text · Article · Mar 2008
    • Accordingly , capillary loss may have led to the significant decrease of venous RFV in the occluded region after IVB. In addition, the level of vascular endothelial growth factor (VEGF) in the vitreous fluid is correlated with the nonperfused retinal area in BRVO patients [11]. VEGF has been shown to stimulate the production of nitric oxide (NO), an endothelium-derived relaxing factor [12] .
    [Show abstract] [Hide abstract] ABSTRACT: Background Although intravitreal injection of bevacizumab (IVB) is effective for macular edema in patients with branch retinal vein occlusion (BRVO), the changes of retinal hemodynamics remain unclear. We investigated retinal hemodynamic changes in BRVO patients after IVB by performing laser speckle flowgraphy (LSFG). Methods In 35 BRVO patients with macular edema, the relative flow volume (RFV) of the retinal artery and vein passing through the optic disc was measured in both the occluded and non-occluded regions of the retina before IVB and 1 month after IVB by LSFG. The ischemic region of retina was measured with the Scion Image program and the severity of retinal ischemia was assessed by dividing the non-perfused area by the disc area. Results Macular edema improved significantly by 1 month after IVB. The venous RFV ratio showed a significant increase in the non-occluded region at 1 month after IVB. There was a significant negative correlation between the venous RFV ratio and the severity of retinal ischemia in the occluded region. On the other hand, arterial RFV ratio showed no significant change after IVB in either the occluded or non-occluded region. In addition, there was no significant correlation between the arterial RFV ratio and the severity of retinal ischemia in either the occluded or non-occluded region. Conclusions These results suggest that an increase of retinal venous outflow after IVB may possibly influence the resolution of macular edema and that the response of venous outflow after IVB depends on the severity of retinal ischemia in the occluded region.
    Full-text · Article · Dec 2016
    • 7a and b]and can even be used to confirm and observe the re‑attachment of the ciliary body. [83]
    [Show abstract] [Hide abstract] ABSTRACT: Anterior segment imaging allows for an objective method of visualizing the anterior segment angle. Two of the most commonly used devices for anterior segment imaging include the anterior segment optical coherence tomography (AS-OCT) and the ultrasound biomicroscopy (UBM). AS-OCT technology has several types, including time-domain, swept-source, and spectral-domain-based configurations. We performed a literature search on PubMed for articles containing the text "anterior segment OCT," "ultrasound biomicroscopy," and "anterior segment imaging" since 2004, with some pertinent references before 2004 included for completeness. This review compares the advantages and disadvantages of AS-OCT and UBM, and summarizes the most recent literature regarding the importance of these devices in glaucoma diagnosis and management. These devices not only aid in visualization of the angle, but also have important postsurgical applications in bleb and tube imaging.
    Full-text · Article · Nov 2015
    • This may further increase the chance for the inferior RNFL of eyes with long axial lengths to be diagnosed a false positive, that is, thinner than normal as in a typical case (arrow inFig. 2 bottom). In the early stages of glaucoma in myopic eyes, the RNFL defects are more likely to be detected in the paracentral infero-temporal and supero-temporal sectors (Greve & Furuno 1980; Araie et al. 1995; Mayama et al. 2002). However, in moderate-to-high myopic eyes, the RNFL of the temporal sectors is thicker than that in the normative database (arrowheads inFig. 2 bottom).
    [Show abstract] [Hide abstract] ABSTRACT: PurposeTo determine the effect of the axial length on the supernormal and false-positive sectors of the peripapillary retinal nerve fibre layer (RNFL) in healthy eyes using the normative database embedded in a spectral domain optical coherence tomographic (SD-OCT) instrument.Methods This was a prospective, observational cross -sectional study. The right eyes of 126 healthy young volunteers were studied. The RNFL thickness was measured by SD-OCT in twelve 30-degree sectors (clock hours) around the optic disc. The sectors whose RNFL thickness was <5% probability level were labelled as false-positive sectors. The sectors >95% probability level were labelled as supernormal sectors. The relationships between the axial length and rates of supernormal and false-positive sectors were investigated.ResultsA longer axial length was significantly associated with an increase in the rates of supernormal thickness in sector 8 (odds ratio, [OR], 1.494; p = 0.010) and sector 10 (OR, 1.529; p = 0.008). The supernormal sectors were mainly located in the temporal region. A longer axial length was significantly associated with a higher rates of false positives in sector 5 (OR, 1.789; p = 0.017), sector 6 (OR, 2.305; p < 0.001) and sector 12 (OR, 2.277; p = 0.035).Conclusions The axial length was significantly related to the rates of supernormal and false-positive sectors even in healthy eyes. These findings indicate that the specificity and sensitivity of SD-OCT will be affected especially in eyes with longer axial lengths.
    Article · Mar 2014
    • Compliance with topical medications is likely linked to comfort issues. Multiple studies have demonstrated brinzolamide to be more comfortable and preferred by patients to dorzolamide, the other major topical carbonic anhydrase inhibitor available for treatment of glaucoma.13,17,29–31 In a prospective, double-masked, randomized, active-controlled, crossover, multicenter study, patients were asked to evaluate ocular discomfort associated with the brinzolamide-timolol fixed combination versus the dorzolamide-timolol fixed combination.
    [Show abstract] [Hide abstract] ABSTRACT: Glaucoma encompasses a wide clinical spectrum of disease, with the common pathophysiology of progressive optic neuropathy leading to visual field loss. Elevated intraocular pressure (IOP) is a key risk factor in disease progression. Treatment is aimed at reduction of IOP to minimize continued optic nerve head damage. Pharmacologic treatment with various classes of IOP-lowering medications is generally employed before more aggressive surgical interventions. Monotherapy is generally accepted as initial therapy for glaucoma, but at least half of patients may require more than one IOP-lowering medication. One option is the fixed combination of brinzolamide 1% and timolol maleate 0.5%, which is commercially available in some countries as Azarga(®) for treatment of glaucoma not adequately responsive to monotherapy. These agents may also be used in an unfixed fashion, but fixed combination therapy is generally more convenient for patients, which may result in improved compliance, a reduction of the "washout effect" from instilling multiple drops, and a potential reduction in the side effects related to multiple doses of preservatives.
    Full-text · Article · Sep 2011
    • where n is the number of observation points (n ∈ [2, 10] ) and N (n) is the number of patients in the test dataset. The value of a i (n) is 1 − RMSE f (i) RMSE LR (i) if n < L i , and 0 otherwise.
    [Show abstract] [Hide abstract] ABSTRACT: This study addresses the issue of predicting the glaucomatous visual field loss from patient disease datasets. Our goal is to accurately predict the progress of the disease in individual patients. As very few measurements are available for each patient, it is difficult to produce good predictors for individuals. A recently proposed clustering-based method enhances the power of prediction using patient data with similar spatiotemporal patterns. Each patient is categorized into a cluster of patients, and a predictive model is constructed using all of the data in the class. Predictions are highly dependent on the quality of clustering, but it is difficult to identify the best clustering method. Thus, we propose a method for aggregating cluster-based predictors to obtain better prediction accuracy than from a single cluster-based prediction. Further, the method shows very high performances by hierarchically aggregating experts generated from several cluster-based methods. We use real datasets to demonstrate that our method performs significantly better than conventional clustering-based and patient-wise regression methods, because the hierarchical aggregating strategy has a mechanism whereby good predictors in a small community can thrive.
    Article · Mar 2016 · Journal francais d'ophtalmologie
    • В группе, где постоянно применяли дорзоламид, давление снизилось с 18,0 до 17,9 мм рт.ст. [40]. Говоря о гипотензивном лечении пациентов с глаукомой, зачастую забывают о недостаточности определения и рекомендации пациенту того или иного эффективного препарата.
    [Show abstract] [Hide abstract] ABSTRACT: The review discusses the characteristics of brinzolamide, topical carboanhidrase inhibitor, summarizes the experience of its clinical use in glaucoma as monotherapy, combined with other hypertensive medications, in cases of inflammatory pathology of the anterior segment of the eye or increase of intraocular pressure after cataract extraction. The analysis of studies of influence of this medication on ocular blood flow is given.
    Article · Jan 2010 · Journal francais d'ophtalmologie
    • Prior work in India has examined barriers and facilitators that aff ect adherence to antiretroviral medications and the patt erns of prescribing and dispensing of medications by pediatric resident physicians. [5][6][7]Despite the availability of effective medications for glaucoma and greater awareness of the importance to follow these treatment regimens, patient nonadherence to prescribed therapy continues to be a signiÞ cant problem. [8,9] The purpose of the current study was to (1) describe the diff erent types of problems reported by the patients in India when taking their glaucoma medications and (2) examine the relationship between patient-reported problems in taking their glaucoma medications and patient adherence to treatment.
    [Show abstract] [Hide abstract] ABSTRACT: We describe the occurrence of bilateral iridocorneal endothelial (ICE) syndrome with glaucoma in a young girl with Down's syndrome. A 16-year-old girl with Down's syndrome was found to have secondary glaucoma in the right eye with features of progressive iris atrophy in both eyes. She was uncontrolled on maximum tolerable medical therapy for glaucoma. She underwent an uneventful trabeculectomy with mitomycin-C in her right eye. Scanning electron microscopy of the trabecular meshwork obtained in this case is described.
    Full-text · Article · Mar 2009
    • These parameters relating to patient understanding also improved compliance with the treatment regimen. Our previous study also suggested that the factors influencing patients' adherence were the number of ophthalmic solution, age, the taste of the ophthalmic solution, administration intervals, the number of drops and washing hands before applying the ophthalmic solution, though the subject numbers were small (Ikeda et al. 2001). In conclusion, the clinical significance of proper application technique was evaluated in Japanese glaucoma patients to find factors influencing pharmacological effects.
    [Show abstract] [Hide abstract] ABSTRACT: The clinical significance of a proper eye drop application technique was evaluated in Japanese glaucoma patients. Patients diagnosed with primary open-angle glaucoma having intraocular pressure (IOP) greater than 21 mmHg were treated with eye drops at home. In some patients, however, the topical treatment was ineffective. They returned to the hospital to receive surgical treatment. On admission, 56% of these patients had IOP greater than 21 mmHg. Patient instillation technique was evaluated based on the proximity of the eyedropper tip to the eyes, application position, eyelid closure, treatment (removal) of excess fluid, and nasolacrimal occlusion. In addition, pharmacists interviewed patients to determine the level of understanding of glaucoma, knowledge of prescribed drugs, home application technique, and sensation after application. Multivariate analysis revealed that the key factors influencing the control of IOP to less than 21 mmHg with topical medication were: application of drops in the center of the eye and removal of excessive fluid, in addition to gender and age. Proper topical application at home was dependent on the patient's understanding of the disease, knowledge of prescribed drugs, patient education on the use of drugs, the competence of the instructor, and knowledge of correct application technique. This study indicates that easily comprehensible patient education on the use of eye drops, the nature of glaucoma and the proper use of prescribed drugs is vital to improving the clinical efficacy of topical ophthalmic medication of glaucoma in adult patients.
    Full-text · Article · Feb 2008
    • Une évaluation du temps de transit du flux sanguin rétinien par vidéo-angiographie à la fluorescéine ne montre pas de différence entre les groupes GPAO et GPN [152]. Cependant le flux sanguin rétinien parapapillaire mesuré par LDF chez les patients ayant un GPN est réduit par rapport à un groupe témoin de sujets sains [153].
    [Show abstract] [Hide abstract] ABSTRACT: The exact pathophysiology of glaucoma is not fully understood. Understanding of the vascular pathophysiology of glaucoma requires: knowing the techniques for measuring ocular blood flow and characterizing the topography of vascular disease and the mechanisms involved in this neuropathy. A decreased mean ocular perfusion pressure and a loss of vascular autoregulation are implicated in glaucomatous disease. Early decrease in ocular blood flow has been identified in primary open-angle glaucoma and normal pressure glaucoma, contributing to the progression of optic neuropathy. The vascular damage associated with glaucoma is present in various vascular territories within the eye (from the ophthalmic artery to the retina) and is characterized by a decrease in basal blood flow associated with a dysfunction of vasoregulation. Copyright © 2015. Published by Elsevier Masson SAS.
    Article · Nov 2015